On Friday 07 January 2005 01.03, Kurt wrote: > >Dan, > > > >Here's a pointer to what I did to my Laser Arts wings for strengthening. > > > >http://www.ppssrc.com/carbonwing/carbonwing.html
(snip) > If I were building a woody that required some additional strength > to a wing I would put carbon on the bottoms of both upper and lower spars. > The reasons are this, first, carbon fiber is stronger under tension and > not compression. Doesn't really help to put it on the bottom of the upper spar, as it will still be in compression - the entire top spar is! Easier to sand the top of the spar smooth, though, if the carbon is on the bottom ... If you add carbon it should be twice as thick on top spar than on the bottom, due to its lower compression strength. That's how Lancair does it, too! A thin aluminium rectangular spar, of soft aluminium, is, on the other hand, very strong in compression and could well be -after it surface has been roughened with a heavy file, or similar, be glued to a wooden spar with epoxy, and held in place with kevlar thread. Soft aluminium have good ageing characteristics, both in tension and compression, while harder qualities have less good in compression, and are harder to roughen as well. > Second I would be concerned of the carbon delaminating if > it was on the upper surface of a spar. The other thing that I'd consider > doing is adding the carbon to the spars prior to assembly. I'd even go as > far as using a vacuum bag to apply enough consistent pressure along the > entire surface of the spar & carbon. I have no arguments against this - sound advice as usual! Yours, Tord PS Glad to be back after a while doing other things :-)! RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
